These higher dust temperatures need to be confirmed through multi-frequency observations with ALMA, preferably sampling close to the peak of the dust emission, to measure \(T_\mathrm {dust}\) . For galaxies at \(z\gtrsim 6\) , such observations are time consuming even with ALMA, but they have been achieved for a handful of galaxies so far. [1]} followed-up four \(z\sim 5.5\)  galaxies in Band 8 (sampling rest-frame \(\sim 100\mu \) m, close to the peak of dust emission), which, combined with existing Bands 6 and 7 observations, allowed them to measure dust temperatures \(T_\mathrm {dust} \sim 30-40\,\mathrm {K}\) . In another recent study, [2]} combined Band 9 observations with observations in three other bands (Bands 6, 7, and 8), to constrain a dust temperature of \(T_\mathrm {dust}=42\,\mathrm {K}\)  for a galaxy at \(z=7.13\) .
